JP3742581B2 - Electric vehicle control device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a control device for an electric vehicle, and more particularly to a control device for an electric vehicle that suppresses vehicle body vibration that occurs during sudden start or rapid acceleration.
[0002]
[Prior art]
In recent years, in order to prevent and suppress environmental pollution and noise, electric vehicles (including hybrid vehicles) that run on electric motors have been developed instead of vehicles that run on internal combustion engines such as gasoline engines and diesel engines. As an electric motor that is a driving source of such an electric vehicle, a DC motor or an AC motor is employed, and among them, a three-phase AC synchronous motor (hereinafter referred to as “synchronous motor”) using a permanent magnet as a rotor is high. Due to its efficiency, it is regarded as the mainstream of electric motors for electric vehicles.
[0003]
In an electric vehicle equipped with the above-described synchronous motor, a direct current from a battery mounted on the vehicle is converted into a predetermined alternating current by an inverter, and the synchronous motor is driven by the alternating current to drive the vehicle.
[0004]
At this time, a predetermined torque command value is calculated and output according to the accelerator pedal operation amount (hereinafter referred to as “accelerator operation amount”), and a predetermined current command value is calculated and output according to the torque command value. The output is output and the current according to the current command value is controlled by a predetermined control means while being supplied to the synchronous motor via the inverter to drive and control the synchronous motor. The output torque of the synchronous motor is a predetermined torque. Open loop control is performed so as to follow the command value.
[0005]
[Problems to be solved by the invention]
By the way, in the electric vehicle as described above, the torque transmission system from the output shaft of the synchronous motor to the drive wheel through the differential gear and the drive shaft constitutes a “torsional resonance system” using the drive shaft as a spring element. ing.
[0006]
For this reason, when the accelerator pedal is depressed suddenly, such as when suddenly starting or suddenly accelerating, the output torque of the synchronous motor is controlled by the control means so as to follow it. The “torsional resonance system” resonated and car body vibrations occurred. Due to the occurrence of such body vibration, the ride comfort of the driver and passengers has become extremely poor.
[0007]
The subject of this invention is providing the control apparatus of the electric vehicle which suppresses the vehicle body vibration which generate | occur | produces at the time of sudden start and sudden acceleration, and improves riding comfort markedly.
[0008]
[Means for Solving the Problems]
In order to solve the above problems, the invention described in claim 1 includes a torque command value calculating means for calculating and outputting a predetermined torque command value according to the accelerator operation amount, for example, as shown in FIG. Target current value calculation means for calculating and outputting a predetermined target current value according to the torque command value, and driving control of the motor via the drive means by inputting a current according to the target current value to the motor. In the electric vehicle control device including the drive control means, the target current value calculation means has a predetermined delay with respect to the torque command value when the accelerator operation amount is suddenly increased to shift to the full-open running state. have a delay means for producing said delay means of said target current value calculating means, the target electric against the torque command value when shifting to the fully open running condition rapidly increased the accelerator operation amount Time history of the value is,
I ^* = I ^* _MAX (1-2e− ^τt + e− ^2τt )
(I ^* : target current value, I ^* _MAX : maximum target current value, t: time, τ: positive constant)
It is defined by a function represented by
[0009]
According to the first aspect of the present invention, the target current value calculation means includes delay means for causing a predetermined delay with respect to the torque command value when the accelerator operation amount is suddenly increased to shift to the fully open running state. Therefore, the output torque of the electric motor can be delayed with respect to the torque command value. Further, the time history of the target current value with respect to the torque command value at that time is determined by a specific time function.
[0010]
Therefore, the resonance of the torque transmission system (torsional resonance system) from the output shaft of the electric motor to the drive wheel can be suppressed, and the vehicle body vibration of the electric vehicle can be suppressed. As a result, the ride comfort when suddenly starting or suddenly accelerating can be significantly improved.
[0013]
According to a second aspect of the present invention, in the control apparatus for an electric vehicle according to the first aspect , for example, as shown in FIG.
τ ≦ 5
It is characterized by being set in the range of.
[0014]
According to the second aspect of the present invention, in addition to the function and effect of the first aspect of the invention, the positive constant τ of the time history of the target current value is set within a specific range. It can be set freely within an appropriate range. Accordingly, the delay timing can be freely set within an appropriate range according to the type of electric vehicle, the specification of the electric motor, and the like.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the present embodiment, a control device for an electric vehicle that runs on a three-phase AC synchronous motor (synchronous motor) 10 that is an electric motor will be described.
[0016]
As shown in FIG. 1, the electric vehicle according to the present embodiment includes a battery 20 as a power source, a control device 30 that performs vector control of the synchronous motor 10, and the output of the battery 20 controlled by the control device 30 is converted to AC power. An inverter 40 as a power converter, a resolver 50 as a rotational speed detecting means for detecting the rotational speed of the synchronous motor 10, an accelerator operation amount detector 60 for detecting an accelerator operation amount, and a rotational movement of the synchronous motor 10 as a drive shaft 80. And a drive wheel 90 provided at both ends of the drive shaft 80.
[0017]
The synchronous motor 10 is connected to the drive wheel 90 via a differential gear 70 and a drive shaft 80, and the drive wheel 90 is rotated by the rotational motion of the synchronous motor 10 so as to give a propulsive force to the vehicle. The DC power supplied from the battery 20 to the inverter 40 is converted into three-phase AC power under the control of the control device 30 and supplied to the synchronous motor 10.
[0018]
As shown in FIG. 2, the control device 30 includes torque command value calculation means 31, target current value calculation means 32, and current control means 33. The torque command value calculation means 31 calculates and outputs a predetermined torque command value T ^* according to the accelerator operation amount A detected by the accelerator operation amount detector 60 and the rotational speed N of the synchronous motor 10 detected by the resolver 50. The target current value calculating means 32 calculates a predetermined target current value I ^* according to the torque command value T ^* and outputs a current command value I ^* ′ according to this.
[0019]
The current control means 33 generates a PWM signal by a PWM signal generation unit (not shown) according to the current command value I ^* ′ and outputs the PWM signal to the inverter 40. The PWM signal causes the switching element of the inverter 40 at a predetermined timing. It functions to control the synchronous motor 10 by performing an on / off operation.
[0020]
As shown in FIG. 3, the target current value calculation means 32 includes basic target current value calculation means 32a, target current value delay means 32b, and target current value switching means 32c. The basic target current value calculation means 32a calculates and outputs the basic target current value I ₀ ^* based on the torque command value T ^* and the rotational speed N. The target current value delay means 32b calculates and outputs a delayed target current value I _d ^* that causes a predetermined delay with respect to the input torque command value T ^* .
[0021]
The target current value switching means 32c starts from the vehicle stop state (state where the accelerator operation amount is 0%) until the accelerator operation amount A is suddenly increased to reach the fully open travel state (travel state when the accelerator operation amount is 100%). Before the elapse of a predetermined time (hereinafter referred to as “switching time”), the delay target current value I _d ^* output from the target current value delay means 32b is set as the target current value I ^*, and after the elapse of the switching time. , The basic target current value I ₀ ^* output from the basic target current value calculating means 32a is set as the target current value I ^*, and a current command value I ^* ′ corresponding to this is output. The switching time described above can be arbitrarily set according to the vehicle type of the electric vehicle, the standard of the synchronous motor 10, and the like.
[0022]
Next, vehicle body vibration suppression control operation using the control apparatus for an electric vehicle according to the present embodiment will be described.
[0023]
First, the accelerator pedal of the electric vehicle in a stopped state (accelerator operation amount 0%) is suddenly depressed to start suddenly and shift to a fully open travel state (travel state with accelerator operation amount 100%). In this state, the torque command value T ^* is calculated and output as needed according to the accelerator operation amount A and the rotational speed N of the synchronous motor 10, and the target current value I ^* is calculated as needed according to this torque command value T ^*. The synchronous motor 10 is driven and controlled by outputting a PWM signal corresponding to the target current value I ^* to the synchronous motor 10 via the inverter 40.
[0024]
The output torque of the synchronous motor 10 is controlled to follow the torque command value T ^* described above. Conventionally, as shown in FIG. 6, the conventional time history of the output torque T of the synchronous motor 10 rises suddenly from the time when the accelerator pedal is depressed (0.2 seconds), but suddenly rises from the middle. The degree decreased and reached a maximum value of 100 (N · m).
[0025]
In this way, when the accelerator pedal is suddenly depressed to shift to the fully open running state, a torque transmission system (torsional resonance) from the output shaft of the synchronous motor 10 to the drive wheels 90 via the differential gear 70 and the drive shaft 80 is achieved. System) resonates and vehicle body vibration occurs.
[0026]
In order to suppress this vehicle body vibration, in the present embodiment, in a predetermined time (switching time) from when the accelerator pedal of the electric vehicle in a stopped state is suddenly depressed to start suddenly and reach a fully open running state, The target current value delay means 32b and the target current value switching means 32c are used to delay the rise of the target current value I ^* .
[0027]
That is, before the switching time elapses, the target current value switching unit 32c outputs the delayed target current value I _d ^* output from the target current value delay unit 32b as the target current value I ^* , and this delayed target value is output. The synchronous motor 10 is driven and controlled by outputting a PWM signal corresponding to the current value I ^* to the synchronous motor 10 via the inverter 40. In the present embodiment, the switching time is set to 2.0 seconds.
[0028]
In the present embodiment, the time history of the target current value I ^* delayed via the target current value delay means 32b and the target current value switching means 32c is:
_{^{I * = I * MAX (1-2e}} - τ t + e -2 τ t)
It is defined by the function represented by Here, I ^* _MAX is the maximum value of the target current value I ^* , and t is time. The time history of the current that follows the target current value I ^* is as shown in FIG.
[0029]
Also, τ is
τ ≦ 5
In this range, it is a positive constant set according to the vehicle type of the electric vehicle, the standard of the synchronous motor 10, and the like. As the value of τ is decreased, the rise of the target current value I ^* becomes gentler, and the rise of the current that follows this becomes gentler (see FIG. 4). In this embodiment,
τ = 3
Was set.
[0030]
FIG. 5 shows the time history of the output torque T of the synchronous motor 10 obtained as a result of the drive control of the synchronous motor 10 according to the delayed target current value I ^* . That is, the time history of the conventional output torque T shown in FIG. 6 rises rapidly from the time when the accelerator pedal is depressed (0.2 seconds) and reaches the maximum value of 100 (N · m). The time history of the output torque T shown in FIG. 5 gradually rises from the time when the accelerator pedal is depressed (0.2 seconds) and converges to the maximum value of 100 (N · m) after about 1.2 seconds. I understand that.
[0031]
After the switching time (2.0 seconds) has elapsed, the target current value switching means 32c outputs the basic target current value I ₀ ^* output from the basic target current value calculation means 32a as the target current value I ^*. The synchronous motor 10 is driven and controlled by outputting a PWM signal corresponding to the target current value I ^* to the synchronous motor 10 via the inverter 40.
[0032]
According to the control apparatus for an electric vehicle according to the present embodiment, the rise of the target current value I ^* with respect to the torque command value T ^* in a predetermined time until the accelerator operation amount A is suddenly increased to reach the fully open traveling state. Therefore, the output torque T of the synchronous motor 10 can be delayed with respect to the torque command value T ^* .
[0033]
Therefore, the resonance of the torque transmission system (torsional resonance system) from the output shaft of the synchronous motor 10 to the drive wheel 90 can be suppressed, and the vehicle vibration of the electric vehicle can be suppressed. As a result, the ride comfort when suddenly starting or suddenly accelerating can be significantly improved.
[0034]
Further, according to the control apparatus for an electric vehicle according to the present embodiment, the time history of the target current value I ^{* with} respect to the torque command value T ^* when the accelerator operation amount A is suddenly increased to shift to the fully open traveling state. However, since it is determined by a specific time function, the resonance of the torque transmission system (torsional resonance system) from the output shaft of the synchronous motor 10 to the drive wheels 90 can be more effectively suppressed.
[0035]
Furthermore, a according to the control apparatus for an electric vehicle according to the present embodiment, for setting a positive constant target current value I ^* of the time history τ in a specific range, the rise of the pace at which the target current value I ^* proper It can be set freely within the range. Accordingly, the delay timing can be freely set within an appropriate range according to the type of the electric vehicle, the specification of the synchronous motor 10, and the like.
[0036]
【The invention's effect】
According to the first aspect of the present invention, the output torque of the electric motor can be delayed with respect to the torque command value. Further, the time history of the target current value with respect to the torque command value when the accelerator operation amount is suddenly increased to shift to the fully open traveling state is determined by a specific time function. Therefore, the resonance of the torque transmission system (torsional resonance system) from the output shaft of the electric motor to the drive wheel can be suppressed, and the vehicle body vibration of the electric vehicle can be suppressed. As a result, the ride comfort when suddenly starting or suddenly accelerating can be significantly improved.
[0038]
According to the second aspect of the present invention, the effect of the first aspect of the invention can be obtained, and the rise and fall of the target current value can be freely set within an appropriate range. Accordingly, the delay timing can be freely set within an appropriate range according to the type of electric vehicle, the specification of the electric motor, and the like.
[Brief description of the drawings]
FIG. 1 is a schematic diagram for explaining a system configuration of an electric vehicle according to an embodiment of the present invention.
FIG. 2 is a block diagram for explaining a configuration of a control device for the electric vehicle shown in FIG. 1;
FIG. 3 is a block diagram for explaining a configuration of target current value calculation means shown in FIG. 2;
4 is a graph showing a time history of a current that is made to follow the target current value obtained by the target current value delay means shown in FIG. 3; FIG.
FIG. 5 is a graph showing a time history of the output torque of the electric motor when vehicle body vibration suppression control is performed using the control device for an electric vehicle according to the embodiment of the present invention.
FIG. 6 is a graph showing a time history of output torque of a conventional electric motor.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Three-phase alternating current synchronous motor 20 Battery 30 Control apparatus 31 Torque command value calculating means 32 Target current value calculating means 32a Basic target current value calculating means 32b Target current value delay means 32c Target current value switching means 33 Current control means 40 Inverter 50 Resolver 60 Accelerator operation amount detector 70 Differential gear 80 Drive shaft 90 Drive wheel

Claims (2)

Torque command value calculating means for calculating and outputting a predetermined torque command value according to an accelerator operation amount; target current value calculating means for calculating and outputting a predetermined target current value according to the torque command value; In a control device for an electric vehicle comprising drive control means for driving and controlling the electric motor through drive means by inputting a current according to a target current value to the electric motor,
The target current value calculating means includes
To the torque command value when shifting to the fully open running condition rapidly increased the accelerator operation amount, have a delay means for generating a predetermined delay,
The delay means of the target current value calculating means is
The time history of the target current value with respect to the torque command value when the accelerator operation amount is suddenly increased to shift to the full-open running state,
I ^* = I ^* _MAX (1-2e− ^τt + e− ^2τt )
(I ^* : target current value, I ^* _MAX : maximum target current value, t: time, τ: positive constant)
A control apparatus for an electric vehicle, characterized by being defined by a function represented by: The positive constant τ of the function is
τ ≦ 5
The electric vehicle control device according to claim 1 , wherein the electric vehicle control device is set within a range.

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